Effects of Dual-Eligible Integrated Care Plans on Medicaid Enrollment and Retention: Evidence From the Implementation of Medicare-Medicaid Plans.

Medicare and Medicaid are separate programs that together cover 13 million low-income older adults and people with disabilities, known as dual-eligible individuals. Concern about a lack of coordination across Medicare and Medicaid has prompted the development of Integrated Care Programs (ICPs). Although the primary goal of ICPs is to coordinate financing and care across Medicare and Medicaid, ICPs may also influence whether low-income individuals obtain or keep Medicaid. We evaluated whether the rollout of Medicare-Medicaid Plans (MMPs)-one of the largest ICPs-was associated with changes in Medicaid take-up and retention among Medicare beneficiaries residing in high-poverty zip codes. Using a stacked difference-in-differences design and variation in MMP rollouts across nine states, we found no evidence that MMPs increased monthly or continuous Medicaid enrollment in this population. These findings highlight the need for focused policies to address Medicaid enrollment gaps among low-income Medicare beneficiaries, which could complement broader integration efforts.